1. Field of the Invention
This invention relates generally to electronic devices, for example solar cells, and to methods of making the same.
2. Technical Considerations
A solar cell or photovoltaic (PV) cell is an electronic device that directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. In a solar cell, photons from sunlight are adsorbed by a semiconducting material. Electrons are knocked loose from their atoms, causing an electric potential difference. Current flows through the semiconductor material to cancel the potential difference. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction.
A typical solar cell includes a glass substrate (cover plate) over which is provided a barrier layer, a transparent conductive oxide contact layer, and a semiconductor layer. A rear metallic layer acts as a reflector and back contact Light scattering or “haze” is used to trap light in the active region of the cell. The more light that is trapped in the cell, the higher the efficiency that can be obtained. However, the haze cannot be so great as to adversely impact upon the transmittance of light through the conductive oxide layer.
It is also desirable that the conductive oxide layer is highly transparent to permit the maximum amount of solar radiation to pass to the semiconductor layer. As a general rule, the more photons that arrive at the semiconductor material, the higher the efficiency of the cell. Further, the conductive oxide layer should be highly conductive to facilitate the transfer of electrons in the cell.
Articles such as Organic Light Emitting Diodes (OLED) and Light Emitting Diodes (LED) also utilize conductive oxide layers and would benefit from enhanced haze and/or high transparency.
It would be desirable to provide a conductive oxide layer having enhanced conductivity and/or light transmission and/or light scattering. It would be desirable to provide a method of modifying a conductive oxide layer to affect (e.g., increase or decrease) one or more of these factors. It would be desirable to provide a conductive oxide layer useful in solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide a coater useful for manufacturing solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide a method of coating a glass substrate on one or both major surfaces to provide a coated substrate useful in solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide an article and/or method to accomplish one or more of the above results.